Automatic telephone system



Sept. 29, 1925.

E. JACOBSEN AUTOMATIC TELEPHQNE SYSTEM Filed May [mreufnr EmzJautvsel-L Sept. 29, 1925.

E. JACOBSEN AUTOMATIC TELEPHONE SYSTEM E mLL Jacntrsan Patented Sept. 29, 1925.

UNITED. STATES PATENT OFFICE.

EMIL JAcoBsEN, oEcr IoAGo, ILLINOIS, ASSIGNOR r0 A 'roMA'rIo ELECTRIC co vI- PANY, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

AUTOMATIC TELEPHONE SYSTEM.

Application filed May 20, 1918. Serial No. 235,436.

To all whom it may concern.

Be it known that I, EMIL JAooBsEN, a citizen of the United States of America, and a resident of Chicago, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in Automatic Telephone Systems, of which the following is a specification.

My invention relates general to a telephone system m which connectlons are established between subscribers by means of automatic switches without the intervention of an operator.

Among theobjects of my invention are to provide means for increasing the capacity of such an exchange system without material addition of apparatus, cut down the operations required of a subscriber in locating a desired called subscribers line, provide new methods of operation to .call a subscriber, provide improved switches to be operated by the subscribers and to generally improve the .efiiciency of such a system and increase its flexibility.

In-the automatic telephone systems which have been installed prior to this time, one of the greatest objections to its acceptance by the public has been the large number of figures which it is necessary to remember I when calling another subscriber by means of an automatic calling device. For instance in a large exchange it is often necessary to send as many as 7 or 8 figures to the switches of the exchange before the called line is reached, and the calling device must be operated a like number of times. Incase a number of private branch exchanges are connected to the system, then a stillgreater number of digits is required and it will be seen that should automatic long distance operation be desired between large cities the number of digits would become very large and hard to remember.

The reason for so many digits being required is that it has been determined that a system operates most efiiciently when the switches have access to 100 trunks or lines only, that is, 10 groups of ten levels of contacts and although the switches might simply be increased by making each switch have access to more trunks or lines, yet, if this were done, the time of operation of the switch would be too long and the digits or directory numbers would be confusing.

In order to accomplish the desired results and provide a system which is free from such difficulties, I have provided automatic selector switches each having access to twice the number of trunk lines (or 200 trunks)- and connector switches having access to four times the usual number (or 400) subscribers lines. To further aid in producing the desired results I have so arranged these large capacity switches that only theregular number of steps (10) both vertical and rotary are required and have provided a calling device which although very similar to that now employed in standard systems, is especially adapted to control the said large capacity switches. I

Having given a general outline of the features and objects otmy invention I will describe the particular embodiment of my invention as shown in the drawings.

Figure 1 shows a calling subscribers line A having a'line switch 0 of the well known rotary type individual thereto and being of the usual common battery type of substation having a receiver 2, transmitter 3, calling device GD, switch hook 4 and its controlling springs, and a resistance. 5in series with the line circuit which is adapted to be cut out of the line circuit by the operation of the springs 6 and 7 which are controlled by the calling device in a manner to be explained.

The line switch Chas access to a plurality of selectors D, which are of the well known Keith Erickson type having vertical motion to elect a group of trunks and rotary motion to select an idle trunk in the group, except that the circuits have been changed somewhat to adapt it to operate in accordance with the principles of my invention. The'selector is providedwith two line banks and two private banks one above the other and has a pair of line wipers and a pair of private wipers cooperating with each line and private bank. Before the switch is operated a relay is controlled which cuts out one or the other of said pairs of wipers so that a trunk line will be selected in either the lower or upper banks, depending upon which set of wipers has beenmade effective.

The selector switch D has access to a num ber of trunk lines in both its upper and lower banks (100 in each bank) so that the trunk lines in the lower level may all lead to repeaters such as E and through said repeaters to connectors such as H (Fig. 2). The trunks'gin the upper level which cooperate with the upper set of wipers may be for local calls only or the trunks in each bank may lead to different groups of switches;

lhe repeaters E are of a well known type of repeater which simplyreceives impulses from a substation and repeats them to "the trunk line to which they are connected ex cept that certain circuit changes have been made to adapt :them 110 .a system embodying my invention.

. Associated. with {each trunk flineiroin a,

repeater .E :are connector, switches H (Fig. 2) ;although it will ibe understood illi tr ele c- ,tor switches similar tothat shown atl) may ..be inserted between ithererjeatersand connectors The connector is of the stand- ,ard Keith Ericksontypejof connector except that it is provided with 4 sets ofwi-pers,

four lineba-nks andfourgpriyate banks, and

is also provided with certain novel means for switching the trunk line ;to any desired setoiwipers.

: In Figures 3 andfi I have shown twIO alternative methods by means of which my i i-- ventionmay be employed, In these figures. I haveshow only ffsubs i s h t arrangement of the .circuit zthereat and the manner of arranging the ,contr'olling relays of :a switch to c p r eth r w h Figure 5 shdwsa front view ot' the call.- .ing device used in iniy improved system showing he a r ngement of t e 'ner 110188 and the spying contacts controlled thereby. itlaiiing g ven the i e era objec s of y invention, .lwi poi t out, in de ai he .qp-

@era' wn .of he syst m, re er nc b ingl t0 theiaccompanying gdrawings. V I

The calling'deyice used .in this system is arranged as shown in Figure with .two rowsfof finger holes, The .numbers in each set of holes being alike exceptthat the .inside row .of figugresirom 1 to0 are printed in red while theoutside .row are printed in black. A pairof make springs are-mount.

v ed as shown undernea'th the front plate of the calling device. and directly in "the ipath of the finger holes oi the outer: or. black number finger holes. Now :if .a subscriber inserts a finger inone-of ,the said routside holes and rotates the {same "around :till fhis finger meetsthe finger slt0p, t hcn as the linger meets the said springs, jthey willjbe closed into contact. The holes {are so 'arranged that if/either the reamblack mimbersare used only ten impulses may b'efs'c'nty That is if the subscriber inserts a finger in the number three (red) hole and op rates the device thr-eeinipulses will be delivered in the. usual mannerasis well known to those versed in the art. It thesubscriber operates the device by using the number three (black) hole then three impulses will also be sent in the usual manner, except that in addition to the three impulses, a circuit will be. closed by the springs "6 and 7 as shown at substation A (Fig. 1).

N ow when the subscriber at A removes his receiver to initiate a call, a circuit will be closed by the switch hooksprings for the line relay 8 of the line switch C in the usual manner, which relay in turn closes a series circuit at springs .9 for switching relay 10 and rotary magnet 11. If the trunk line on which the switch Q is-resting .isbusy then ground from the private wiper lkwillmaintain the relay 10 short circuited and will cause the magnet 1 1: tooperate intermittent 1y to rotate the wipers @to an idle trunk line,

at which time, the sliortcircuiting of relay 10 being discontinued, "said relay energizes over the series circuit to disconnect therelay 8 and ground from the line and to connect the line of substation Q Lthrough its contacts 'tothe wipers 12and l3 alid thence to thetrunk line leading to (the idleselector D. Relay 10 being of a relatively high resistance does not permit the. magnetv 11 "to energize in the above traced series circuit.

' As. soon as relay l0 genergizes a, circuit is closed i'or the line relay 15 .of theselectOr D in series with the Iineoi' substation A and the marginal relay 26 which does not energize in'series with the high resistance 5at the isul istatio n. It will be seen that the subscriber, instead of having tosend 2digits to first pick out one of a.,h'u"nd-red {trunks "by the selector D, and then having to operate another selector .to pick out one of another hundred trunks has access to two hundred trunks directly from the selector there being two banks of 100 lines each. "If {the subscriber desires to call. a. subscriber in .one'group or division of (the exchange, The

,the'directory as 2 .(iedi (red)"5 (,r ed) then thejsubscriber will insertla'tinger in thein'side hole marked 2 (red) andoperate .tliecallmg device in the usual manner to separate the springs CD at the substation, two "times, The relay 15 1n response to thls series of 1mpulses operates to; control the vertical magnet 16 and series relay 17 through contacts of slow relay 1 8 (which isdnaintained energized) to operates'aid magnet to step the wlpers 20-25 "inclusive, up to the second level of their banks. :i L S l dle SWiltlllllgjY- lay '1Q'and marginal relay 26 are deenergizedatthis'tim'e, only'the lower setof'line 'and private wipers are effective, being connected I to the line circuitthrough back contacts of relay l9,while'wipers'20f21and 22 are open. Assoon as the switch steps off normal and springs 27 close, a circuit is closed by relays 18 and 17 through relay 28 to prepare the circuit'of rotary magnet 29. Now when relay 17 falls back after this digit, a circuit'is closed for the rotary magnet 29 through the front contact of relay 18, the back contact of relay 17 and the front contact of relay 28. The magnet 29 operates to step the wipers 20 to onto the first contacts of their respective banks and to open the circuit of relay 28 atsprings 30. As only the private wiper 25 is effective the wipers will be rotated until an idle trunk line in the lower bank is reached without regard to the condition ofthe trunks in the upper, bank. Ground from busy trunks controls relay 28 to perform this trunk selecting operation. When an idle trunk is reached, the relay 31, which has been short circuited by the ground on :the private wiper while passing over busy trunks, energizes in series with relay 28 from ground on springs of relay18. Relay 31 being of comparatively high resistance does notpermit the energization of the relay 28 at this time. Relay 31 upon energizing,*disconnects the magnets of the selector D from the line of substation A and connects said line through to the wipers 23 and 2 1 which it will be assumed have selected and come to. rest uponthe contacts of the lower bank to which the trunk line leading to connector H through the repeater E is connected. As soon as relay 31 energizes the circuit of the line relay 32 of the repeater E is closed, as was the line relay 15 of selector D, in series with the calling line and marginal relay 33. Relay 33 (like relay 26) does not energize in series withthe high resistance 5 at the substation.

The next digit being 4: (red), the subscriber will again operate the dial this time to I send four impulses to the relay 32. Springs 6 and 7 are not operated and the operation of the repeater line relay is as usual, that is, relay 32 by the operation of springs 34 repeats the four impulses of this digit to the line relay 35 of the connector H over a circuit including the resistance 36, which is of the same resistance as that shown at 5 at the'substation. The circuit of the line relay 35 of the connector extends from ground through the lower winding of said relay,

springs 37, off normal springs 38, resistance 36, springs 34:, upper winding of switching relay 39, springs 40, and upper winding of the'line relay to battery. The relay 39 which is included in this circuit is a marginal relay similar to relays 33 and 26 and does not energize in series with resistance36. As this circuit is now interrupted four times in accordance with this digit, the line relay 35 falls back to step the wipers 4152, four steps to the fourth level of their banks by means of the vertical magnet 53, which is energized in the usual manner over a circuit including the back contacts of relay 35, front contacts of relay 5 1, (which is held energized) springs 55, and relay 56 and magnet 53 in series to. battery. As soon as relay 56 energizes and the switchtakes one step, the springs 38 are opened and springs ber being 5 (red) the subscriber will again operate his calling device to send five impulses without shorting resistance 5 at the phone and therefore without shorting the re sistance 36 at the repeater. The line relay 35 will now respond to the impulses of this digit to operate the rotary magnet 59 over a circuit from ground through back contacts of relay 56, springs 60, relay 61, and magnet 59 to battery. Magnet 59 is operated to stop all the wipers 41-52 to the fifth contact of their respective banks. As relays 39 and 62 are in normal position, only the wipe-rs 411, 4-2 and 43 are effective, the other wipers being open at one or the other of said relays- Therefore although the switchH has stepped its wipers in such a manner that each set has connected with a different subscribers line, one at line 63-65, one at line 6668, one at 69-71 and another at 7 2-7 1, still a connection will be extended to only onelof said lines, namely, line 7 274. The subscriber has therefore picked out one of 100 lines by operating a switch by only two digits, each having less than 10 impulses. The relay 61 which energized in series with the rotary magnet, remains energized during the impulses of this digit and for a second thereafter to hold the private wiper 43 connected to the busy test relay 75. If this line is busy, relay will operate in the usual manner to connect a busy tone to the calling subscriber, open the circuit of wiper cut on relay 76, and open the circuit of rotary magnet at springs 60. If the called line is not busy then relay 75 will not energize and as soonas relay 61 falls back a circuit will be closed for" the relay 76 from ground through springs 77, springs 7 9, upper winding of relay 76, springs78, and through the private wiper. 13 to battery through the bridge cut off relay of the called Y to be called whose line is located in the second bank of the connector. If this line is located on the terminal in the second bank which corresponds to the terminal of the previously called subscriber .in the lower bank then this subscribers number will be 2 (red) 4 (red) 5 (black). The operations,

in calling this number will be exactly the same as just described in calling .2 (red) 4 (red) .5 (red) and the connection will be extended to the connector H and the connector 'H' operated both vertical and rotary the same as before except that the lastdigit (5) will in this instance be dialed on the outside row of figures on the dial. Nhenthe number 5 is called on the black or outside row the springs 6 and 7 vare momentarily closed by the finger of the subscriber (or in any other manner) justibetorethetdial is allowed to return tosend the five impulses.

The closure of the springsiti and 7 short circuits the high .resistance 5 at the. telephone and causes the marginal relay 330i the repeater E to energize. Relay 33, upon energizing, in turn short circuits the high resistance 36 in the circuit of the relays 35, 39 and 62 of the connector. The connector having been previously raised from normal the springs 38 are now opened and the circuit of the line relay 35 includes the upper winding of relay 39 and alsothelower winding of relay 62. Relays 62 and 39 are both marginal, that is relay 62 will operatewhen the resistance 36 is shorted but relay 39 will not operate unless both theresistance 36 and the winding of relay 62 are shorted. In this instance then relay (32 will energize and will lock itself to ground through springs 7 7 and .springs 86 and will also disconnect thenor mal wipers 41, 42 and 43 from the line cirquit and connect the line circuit instead to 44, 45 and 46 will be eli'ective andthe con nection will be extended to the substation connectedto line-69-7l in the second b ank instead of to the line in the lower bank.

to call a partly located on line 6668 whose vnumber in this case would be 2 (red) it (black) 5 (red). The selector switch will again be operated in the same manner by this digit 2 (red) "to seize the repeater New when-the second digit is called ,ontlie black dial the resistance 5 is shorted .to ,pull

up the relay 33 to in turn short the resistance 36. As the connectorhas not yet been raised from normal the springs 38 are closed and therefore only the relay"39 is now in the series circuit with the line relay. ow when resistance 36 is shorted, relay 39 will energize, lock itself to ground .t-hrough springs 77 and 87 and will switch the line circuit from thenormal wipers 41, 42 and 43 to the wipers -17 i8 and 49 through its own front contacts and the back contacts ,of relay 62 The last digit to the connector .013- erates it in exactly the same manner .as in the call first described to rotate the wipers .to the fifth contact in the fourth level excepttha't, relay 39, being energized the connection will be extended to the line 6668 instead of 7274. The testingfloperations are alike in all cases except thatthey are performed over different wipers .and a di tt'erent contact is tested in eachcase according tothe wiper made effective.

'Assume now that the subscriber desires to call the line 63 -65 which is located in the fourth or top bank of the connectorswitch H. In this case the digit called would'be 2 (red) 4 (black) 5 (black). The selector D will be again operated to seize the .repeater E by the digit2 (red). The repeater E will again operate as in .the 'lastdescribed call to control the connector H to step :itn four steps and "to lock the relay 39 energized, thereby connecting :the wipers'eti, 48 and L9 to the line circuit. In this case, however, when the last digit -5 (black) is sent, the repeater E again o'peratesto control the connector to step around to the fifth contact and at the same time, by shorting resistance 36, pulls up the relay 62 as in the case ofthe second call described. The relays 39 and 62 will both be locked energizedin this call and therefore the line circuit will be switched through the front contacts of both out said relays to the wipers 50, 51 andl52.

lhe-wiper 52 is the only test Wiper effect-ive therefore and the connectionwillbeiex- "tended to the line 6365 over the line wipers 50 and 51. The release of the connection is exactly the same in each connection, the locking circuits of the relays -39 andl62 .lbe-

ing opened bythe deenergization of the, slow relay 54. a v

'I have now described how a call mayvbe extended through the lower bank of the selector D to any of the lines accessible to connectors H which are accessible from said i130 lower bank. The upper bank of theselector D may lead to an exactly similar set of trunks as are connected to'the lower bank, or said upper bank of the-selector may be connected to long distance trunk lines to another city, or to connectors, similar to H, directly for local calls. Intact thesystem maybe divided up in any desired :manner. without departing from the spirit c t-my in ventionwhich relates mainly to' the method of controlling any desired series of switches.

Assuming that the upper bank otthe selector D leads to connector switches similar to H and that the calling subscriber desires to call some other subscriber whose line; is located in the lower bank of the connector switch. Now the called subscribers number would be2'(blaclt) 4 (red) 5((red). In this case the first digit will be called on the out side or black row of. figures on the dial, and as the dial is rotated by the subscriber, after the line switch has seized the selector, the springs 6 and 7 short the resistance 5 and cause the-marginal relay 26 to pull up for an instant'to close a circuit at springs 88, for

; the switching re1ay19. Relay l9 energizes to lock itself to ground atthe springs of therelease relay 18 and also connects the hue circuit to thewipers 20,21 and 22 instead of to the wipers 23, 24. and 25. i The selector will be operated in exactlythe same manner as beforepointed out except that, the wiper 25 being open, the switch willptest trunks in the second level of the upper bank instead of testing the trunks in the second level ot the lower bank, and will connect with'some trunk such as B whichleads to a connector or another selector. The last two digits 4 (red) 5 (red) will be sent' by the inner figures on :the dial and will operate the connec.

. torswitch to extend thecall over the fifth contact of the fourth level of the lower bank of such connector. I have shown therefore that a subscriber after seizing the selector D may operate it by one digit of ten or less impulses to pick out an idle trunk in either of two large groups of trunk lines,jthe group being determined by the row of figures on the dial used, and that after extending the call to the desired group of trunks he may operate a connector switch by means of two digits of ten or less impulses each to pick out any lines in tour-large groups of 100 lines each, the group again being determined by the row of figures on the dial used. It

. will be understood that the trunking in this sired. Y

case may be more than ten percent, ,thatis, more than ten connectors may be assigned to one group of 100 lines andeach level of the selectors may have 2Q 01'25 trunksas de- In Figures 3 and ll have shownalternate methods of arranging the substatlon circuit and the switching relays of the wipers. Referring to Fig. 3, instead. of having have showna pair of springs 6 and 7: for

groundingone side of the line to pull ,up

differential irelay 26' which will perform the same functions as the relay 26 (Fig. 1).

In Fig. 4, I have, shown the springs 6, and 7 which operate the same as springs 6 and 7 (Fig. 1) except that they include a high resistance in the line circuitinstead of short ing a high resistance, to cause a marginal relay 26"; to operate to control the switching over of the wipers-1 It will be understood that these alternative methods might be applied to the switchesD, E and H without any-important changes in the circuits, as show n i y 1 Having fully .descri'bedaand ascertained my invention what I consider to be new and desire to. have protected by] Letters Patent will be pointed out in the appended claims.

l/Vhat 1' claim as my invention is: '1. Ina telephone system, a calling line, an automatic switch associated with said line having a pair of wipers, anelement for moving said wipers, a calling device associated with the line for controlling said switch, and means in the switch for automatically rendering an alternate one of said Wipers effective after the element has been moved in response to the firstdigit andbefore the element is moved in response to. the second digit. a Q w 2. In a telephone system, a callingline, an automatic switch associated with said line, other lines accessible to said switchdivided into groups, a device associated with saidcalling line for operating the switch to extend connections from said calling line to said other lines, andnieans associated with said switch and automatically controlled after the switch is operated in response to the first digit and before the switch is operated in response to the second digit tor predetermining the group into which the connection is to be extende j 3; In a telephonesystem, a callingline having an automatic switch associate-d there. with having access to a plurality of large groups of lines, each group being further dividedzinto sub-groups, said switch having motion in one plane to elect one of said subgroups and in anotherplane to select a line in theelected sub-groups, and means asso ciated withthe switch and automatically operated for electing a group of said lines,-said group electing means operable either before the switch is moved or after ithas movedin one plane. l T 1.71

4:. In a telephone system, a calling? line' having an automatic switch associated therewith having access 'toia plurality of large groups oflin'es, each group being further divided into sub groups, said switch having. motion in one plane to elect one of said sub? g ps a ii arbiter plane is el ct a line in the elected sub-group, and means; associated with the switch and automatically operated for electing a group of said lines, said group electing means operable in part before the switch has moved ingeither plane and'in part after the switch has moved in one plane. a

5. In; a telephone system, a line, an automatic switch for said line having a plurality of series" of wipers associated therewith, each series for extending connections into different groups of lines, a calling device for'opcrating saidswitch to: move said wipers into engagement with called lines, and means antomatically controlled by said calling device independent of the operation, for moving the Wipers, for limiting the, call ,t o-one of saidseriesof wipersbcfore the switch is opera-ted and for limiting the call to one wiper in the elected erated,v I

6,, In a telephone system, an automatic switch, a line leadingthereto; alha-l-l-ingdeseries afterth'e swit h isv (0.1

., vice for sending-impulses of current'fltosaid,

switch, a repeater-interposed; insai'd line op-- erated'by' the callin g 'vdevice torepeat said impulses; therefrom to said; switch, means controlled by the calling device for transmit ting an in-rpulse-of increased strength to said repeater, said repeatenrespensive to: said impulse o'fiincrcase'd strengthto transmit animpulse of increased strength to the auto- Ina-tic switch. I I I l l 7311i, a'teliephone sys'tem, an impulse re.- peat'er, an automatic switch, a callin g device for transmitting [impulses of one character to said, repeater, in accordance with a; di it of a called numher, means in the repeater repeating said impulses to said automatic switchto operatecsaid' switch, means assocjated with said calling device for transmitting an'i'mpulse; of the same duration but of a different electrical character to said" repeater'over'the same circuit preliminary to the,. PL1lses of a digit, and means in the repeater" for repeating said impulse of dif-V fere-n-t clrar-acterto the automatic switch.

8Ina telephcne system,"a-n impulse 1e: peater, autonratic switch, a calling device .cl transmitting impulses of difl'erent' strength to said repeater, and means in the repeater responsive to weak impulses for transmitting weak impulses to the switch to periornr one operation thereof and responsiveto strong impulses to transmit strong impulses to-"the switch to perform a, different operation thereof;

9. In a telephone system, a trunk linejhawing two inductivelyconnected'sections, a pair at relaysin bridge of one section, a call in device ile-r transmitting impulses of di f ferent character; over one se c-tion ofjsaijd trunk line, one ofsaidfrela s responsive to impulses one ch aracter: to repeat impulses of a cor-responding character over the othersection, and the other relay responsive toimpulsesof another character to repeat impulses of that character over the other sec- .tion.

10'. In a telephone system, an automatic switch, a line leading thereto, a plurality of Wiper sets therefor, a calling device on said line having mechanism for sending impulses to said switch to operate the same, auxiliary mechanism associated with the device for sendingirnpulses of a particular character to theswitch at certain ti'rnes'to pick out one of said sets of wipers, and a repeater interposed in saidline for receiving both characters of impulses and repeating them to said automatic switch.

11. In atelepjhone system, a calling line, an automatic switch having two sets of wipers, means for extendingsaid line to said switch, a resistance normally connected in series with the line at the subscribers station, a marginal relay included in the line at said switch for controlling the wiper selection, said relay being inoperative because of said resistance, and contacts in the subscribei s calling device forsh'ort circui-ti ng said resistance to oper-' ate said relay.

121 In a telephone system, an automatic controlled by said relay for switching from' one set of wipers to the other, and contacts 'uisa-i'd 'calling device for short circuiting said resistance to operate said relay whenever said calling device is operated from a finger hold in a particular row.

13. In a'telephone system, a selector and a connector for connecting a calling and called line, controlling circuits for said switches each including the two sides oi the calling line in series, connecting mechanism in each switch requiring the associated control circuit to'be first closed and then altered in two different ways in order to secure correct operation in establishing aconnection, means at thestation on the calling line for closing saidcirc-uits and for providing the required circuit alterations, a repeater interposed between s'aid; selector and connector, a trunk line-between the repeater and the connector, and means in the repeater for repeating the alteratiens producedin' the: connector control circuit'tosaid connector, over the two sides of said trunk line in series.

Signed by me at "Chicago, Cook County, State'of Illinois, this 10th day oi April, 191s.

can Montana 

